The Difference Between an Ionic Bond and a Covalent Bond

The difference between an ionic bond and a covalent bond is that

A) ionic bonds commonly occur between two metals and covalent bonds occur between metals and nonmetals.
B) ionic bonds are between atoms that can share electrons; covalent bonds are between atoms that will donate/accept electrons.
C) covalent bonds come about because of a sharing of electrons; ionic bonds do not.
D) ionic bonds are between smaller atoms; covalent bonds are between large atoms.